Elastomeric bush bearings or rubber bushings of this kind with hydraulic damping consist of an inner part, which is generally metallic and essentially cylindrical in shape, a bearing element arranged concentrically with respect to the inner part and connected with it by means of vulcanization, and an outer shell that accommodates the inner part with the bearing element. At least two chambers for accommodating elastomeric damping medium, which are mutually connected via a damping medium channel and are spatially separated in peripheral direction by means of partitions of the bearing element extending in radial direction, are constructed between the outer contour of the elastomeric body and the outer shell by means of this outer body. The damping medium chambers and the channel connecting these form a hydraulic damping system that supports the radial damping effect of the bearing in the area of the chambers. Correspondingly designed hydrobushings are known, for example, from DE 38 18 287 A1 and DE 102 13 627 A1.
According to the state of the art, it is customary to calibrate appropriate bush bearings after introducing the rubber-metal parts formed by the inner part and the bearing element into the outer shell by means of a reduction of its outer diameter. In this way, the elastomer of the bearing element is acted upon by prestressing, and the hydraulic damping of the bearing is increased. The swelling walls are exposed to increased load in the chambers or in the damping medium accommodated therein based on the overpressure generated therein, whereby the stability under load or the durability of the bearing is reduced in a disadvantageous manner. The spring rate ratios that can be achieved in this way are nonetheless comparatively limited between the partitions running in radial main stress direction of the bearing, on the one hand, and its other main stress direction running over the chambers, on the other hand, as well as radial main stress direction running over the partitions and axial direction of the bearing, since a greater spreading of the spring rates at the expense of the durability would not be acceptable. With a simultaneously justifiable durability, the spring rate ratios from the state of the art of known hydraulically damping rubber bushings amount to approximately 5:1 radially over the partitions separating the chambers to radially over the chambers (with reference to the axle carrier bearing:transversal vehicle direction to longitudinal vehicle direction) or approximately 6:1 radially over the partitions to axially (with reference to the axle carrier bearing:transversal vehicle direction to vertical vehicle direction). Higher spring rate ratios with regard to the different case of operation and a best possible driving comfort are definitely desirable in many cases.